Crimson Trace MVF (Modular Vertical Foregrip) 515 (unknown explanation of number).

Anyone have any experience with these? Comments?

Supposedly they contain a laser and light within the foregrip. 5mW laser and 150/200 lumen light. Option of Red or green laser...

Durabuility etc?

I think it'd be a great way to get some weight off the front of the AR..

Lookin for opinions.